A shaft grounding and monitoring system may include a grounding member slidingly engageable with a rotating shaft. An electrical sensor may be configured to be coupled with the grounding member in order to detect an electrical parameter that provides an indication of electricity flowing from the rotating shaft to ground through the grounding member. A processor may be operably coupled with the electrical sensor and may receive and analyze data from the electrical sensor at multiple sampling points taken at different rotational positions of the rotating shaft during multiple revolutions of the rotating shaft. The processor may be configured to develop, over time, a reconstructed waveform representing a compilation of the periodically sampled values of the data from the electrical sensor through one revolution of the rotating shaft.
|
12. A monitoring system for a device having a rotating shaft and a grounding member positioned in electrical contact with the rotating shaft, the monitoring system comprising:
a voltage sensor configured to sense an electrical voltage in the rotating shaft;
a processor operably coupled with the voltage sensor, the processor configured to receive and analyze data indicative of electrical voltage sensed by the voltage sensor;
a memory operably coupled with the processor and configured to store data processed by the processor that is indicative of the data provided by the voltage sensor;
the processor further configured to periodically sample a value of the data indicative of electrical voltage from the voltage sensor and record each value to the memory; and
the processor further configured to develop, over time, a reconstructed waveform representing a compilation of the periodically sampled values recorded to the memory.
1. A shaft grounding and monitoring system for a device having a rotating shaft, the shaft grounding and monitoring system comprising:
a grounding member configured to make sliding electrical contact with the rotating shaft, the grounding member configured to be connected to ground;
an electrical sensor configured to sense an electrical parameter that provides an indication of electricity flowing through the grounding member,
a processor operably coupled with the electrical sensor, the processor configured to receive and analyze data from the electrical sensor representing the electrical parameter;
a memory operably coupled with the processor and configured to store data processed by the processor that is representative of the data provided by the electrical sensor;
the processor further configured to periodically sample a value of the electrical parameter from the electrical sensor and record each value to the memory; and
the processor further configured to develop, over time, a reconstructed waveform representing a compilation of the periodically sampled values recorded to the memory.
18. A monitoring system for a device having a rotating shaft and a grounding member positioned in electrical contact with the rotating shaft, the monitoring system comprising:
an electrical sensor configured to sense an electrical parameter in the rotating shaft;
a processor operably coupled with the electrical sensor, the processor configured to receive and analyze data indicative of the electrical parameter sensed by the electrical sensor;
a memory operably coupled with the processor and configured to store data processed by the processor that is indicative of the data provided by the electrical sensor;
the processor further configured to periodically sample a value of the data indicative of the electrical parameter from the electrical sensor at a sampling rate that is related to a rotation speed of the rotating shaft such that a particular sampling corresponds to an angular position of the rotating shaft that is rotationally offset from the angular position of the rotating shaft corresponding to an immediately previous sampling, the processor recording each value to the memory; and
the processor further configured to develop, over time, a reconstructed waveform representing a compilation of the periodically sampled values of the data indicative of electrical voltage from the electrical sensor.
2. The shaft grounding and monitoring system of
3. The shaft grounding and monitoring system of
4. The shaft grounding and monitoring system of
5. The shaft grounding and monitoring system of
6. The shaft grounding and monitoring system of
7. The shaft grounding and monitoring system of
8. The shaft grounding and monitoring system of
9. The shaft grounding and monitoring system of
10. The shaft grounding and monitoring system of
the processor is further configured to use the temporally aligned recorded shaft rotational positions to correlate the reconstructed waveform to relative positions of the rotating shaft.
11. The shaft grounding and monitoring system of
13. The monitoring system of
14. The monitoring system of
15. The monitoring system of
16. The monitoring system of
17. The monitoring system of
19. The monitoring system of
20. The monitoring system of
22. The monitoring system of
23. The monitoring system of
|
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/515,108 entitled “MONITORING SYSTEM FOR GROUNDING APPARATUS” and filed Jun. 5, 2017, which application is hereby incorporated by reference in its entirety.
The disclosure generally relates to monitoring systems for monitoring one or more components of a device having a rotating shaft susceptible to having a stray electrical voltage on the shaft. More specifically, the disclosure relates to monitoring apparatus, assemblies, systems and methods of monitoring one or more components, such as a grounding apparatus, of a device having a rotating shaft having a stray electrical voltage on the shaft.
In many devices that include a rotating shaft, such as but not limited to electric generators, electric motors, gear boxes such as windmill gear boxes, compressors, pumps, and the like, stray voltage may build up on the rotating shaft. Apart from any stray voltages resulting from equipment that is not functioning correctly, all rotating shafts inherently generate electric fields from asymmetries in magnetic field distribution between rotor and stator, residual magnetic flux in the shaft, excitation and electrostatic charges. These stray voltages may ultimately exit the rotating shaft through structures such as the bearings supporting the rotating shaft. Over time, this can damage the bearings and/or other components of the device.
In order to prevent current flow through structures like bearings and related components, a grounding apparatus may be used to ground the rotating shaft. Such grounding apparatus may include grounding brushes, grounding straps, grounding ropes and other grounding members configured to ground the rotating shaft of the device. In maritime applications, propulsion shafts may include a grounding apparatus in order to avoid galvanic activity that can otherwise cause erosion. There is a desire to monitor the performance of the grounding apparatus to ensure that the grounding apparatus is performing correctly. There is also a desire to monitor electrical current flowing through the grounding apparatus in order to detect and diagnose potential defects or other problems within the device.
The disclosure is directed to several alternate designs, materials and methods of monitoring the performance of a grounding apparatus for an electric generator, an electric motor, a gearbox, a compressor, a pump, a drive shaft, an axle, or other device including a rotating shaft subject to stray electrical voltage on the shaft.
Accordingly, an illustrative embodiment of the disclosure is a shaft grounding and monitoring system for a device having a rotating shaft. The shaft grounding and monitoring system includes a grounding member configured to make sliding electrical contact with the rotating shaft and configured to be connected to ground. An electrical sensor is configured to sense an electrical parameter that provides an indication of electricity flowing through the grounding member. A processor is operably coupled with the electrical sensor and is configured to receive and analyze data from the electrical sensor representing the electrical parameter. A memory is operably coupled with the processor and is configured to store data processed by the processor that is representative of the data provided by the electrical sensor. The processor is further configured to periodically sample a value of the electrical parameter from the electrical sensor and record the value to the memory and to develop, over time, a reconstructed waveform representing a compilation of the periodically sampled values of the electrical parameter from the electrical sensor.
Additionally or alternatively to any above embodiment, the processor is further configured to sample the value of the electrical parameter from the electrical sensor and record the value to the memory in response to a periodic trigger.
Additionally or alternatively to any above embodiment, the periodic trigger is based upon a rotational speed of the rotating shaft.
Additionally or alternatively to any above embodiment, the periodic trigger is based upon a rotational position of the rotating shaft.
Additionally or alternatively to any above embodiment, the periodic trigger includes an incremental delay so that each successive sampling of an instantaneous value of the electrical parameter from the electrical sensor includes a different portion of a successive waveform.
Additionally or alternatively to any above embodiment, the value of the electrical parameter from the electrical sensor includes an amplitude of a waveform representing the electrical parameter from the electrical sensor.
Additionally or alternatively to any above embodiment, the electrical sensor includes an electrical current sensor or an electrical voltage sensor.
Additionally or alternatively to any above embodiment, the processor is further configured to correlate the reconstructed waveform to relative positions of the rotating shaft in order to determine where on the rotating shaft any anomalous or threshold conditions may be occurring.
Additionally or alternatively to any above embodiment, the processor is further configured to utilize an indication of shaft rotational speed and a known sampling rate to correlate the reconstructed waveform to relative positions of the rotating shaft.
Additionally or alternatively to any above embodiment, the processor is further configured to, when periodically sampling a value of the electrical parameter from the electrical sensor and recording the value to the memory, to also record to the memory a corresponding shaft rotational position that is temporally aligned with the value of the electrical parameter from the electrical sensor, and the processor is further configured to use the temporally aligned recorded shaft rotational positions to correlate the reconstructed waveform to relative positions of the rotating shaft.
Additionally or alternatively to any above embodiment, the processor is further configured to analyze the reconstructed waveform to look for anomalous or threshold conditions that may be occurring.
Another illustrative embodiment of the disclosure is a monitoring system for a device having a rotating shaft and a grounding member positioned in electrical contact with the rotating shaft. The monitoring system includes a voltage sensor configured to sense an electrical voltage in the rotating shaft and a processor that is operably coupled with the voltage sensor and is configured to receive and analyze data indicative of electrical voltage sensed by the voltage sensor. A memory is operably coupled with the processor and is configured to store data processed by the processor that is indicative of the data provided by the voltage sensor. The processor is further configured to periodically sample a value of the data indicative of electrical voltage from the voltage sensor and record the value to the memory and to develop, over time, a reconstructed waveform representing a compilation of the periodically sampled values of the data indicative of electrical voltage from the voltage sensor.
Additionally or alternatively to any above embodiment, the processor is further configured to sample the value of the data indicative of electrical voltage from the voltage sensor and record the value to the memory in response to a periodic trigger.
Additionally or alternatively to any above embodiment, the periodic trigger is based upon a rotational speed and/or angular position of the rotating shaft.
Additionally or alternatively to any above embodiment, the periodic trigger includes an incremental delay so that each successive sampling of a value of the data indicative of electrical voltage from the voltage sensor includes a different portion of a successive waveform.
Additionally or alternatively to any above embodiment, the value of the data indicative of electrical voltage from the voltage sensor includes an amplitude of a waveform representing data indicative of electrical voltage from the voltage sensor.
Additionally or alternatively to any above embodiment, the processor is further configured to analyze the reconstructed waveform to look for anomalous or threshold conditions that may be occurring.
Another illustrative embodiment of the disclosure is a monitoring system for a device having a rotating shaft and a grounding member positioned in electrical contact with the rotating shaft. The monitoring system includes an electrical sensor that is configured to sense an electrical parameter in the rotating shaft and a processor that is operably coupled with the voltage sensor and is configured to receive and analyze data indicative of the electrical parameter sensed by the electrical sensor. A memory is operably coupled with the processor and is configured to store data processed by the processor that is indicative of the data provided by the electrical sensor. The processor is further configured to periodically sample a value of the data indicative of the electrical parameter from the electrical sensor at a sampling rate that is related to a rotation speed of the rotating shaft such that a particular sampling corresponds to an angular position of the rotating shaft that is rotationally offset from the angular position of the rotating shaft corresponding to an immediately previous sampling, the processor recording each value to the memory. The processor is further configured to develop, over time, a reconstructed waveform representing a compilation of the periodically sampled values of the data indicative of electrical voltage from the electrical sensor.
Additionally or alternatively to any above embodiment, the sampling rate is related to the rotation speed of the rotating shaft such that a particular sampling corresponds to an angular position of the rotating shaft that is rotationally advanced of the angular position of the rotating shaft corresponding to an immediately previous sampling.
Additionally or alternatively to any above embodiment, the sampling rate is related to the rotation speed of the rotating shaft such that a particular sampling corresponds to an angular position of the rotating shaft that is rotationally retarded of the angular position of the rotating shaft corresponding to an immediately previous sampling.
Additionally or alternatively to any above embodiment, the electrical sensor includes a voltage sensor.
Additionally or alternatively to any above embodiment, the value of the data indicative of the electrical parameter includes an amplitude of a waveform representing data indicative of electrical voltage from the voltage sensor.
Additionally or alternatively to any above embodiment, the processor is further configured to analyze the reconstructed waveform to look for anomalous or threshold conditions that may be occurring.
The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The Figures, and Detailed Description, which follow, more particularly exemplify some of these embodiments.
The invention may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which:
While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.
For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.
All numeric values are herein assumed to be modified by the term “about,” whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the terms “about” may include numbers that are rounded to the nearest significant figure.
The recitation of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
It is noted that references in the specification to “an embodiment”, “some embodiments”, “other embodiments”, etc., indicate that the embodiment described may include one or more particular features, structures, and/or characteristics. However, such recitations do not necessarily mean that all embodiments include the particular features, structures, and/or characteristics. Additionally, when particular features, structures, and/or characteristics are described in connection with one embodiment, it should be understood that such features, structures, and/or characteristics may also be used connection with other embodiments whether or not explicitly described unless clearly stated to the contrary.
The following detailed description should be read with reference to the drawings in which similar structures in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure.
A variety of devices include a rotating shaft that makes contact with a stationary or largely stationary electrical conductor. Examples include but are not limited to electric machines such as dynamo-electric machines including electrical generators and electrical motors. For illustrative purposes, the disclosure will make reference to an electrical machine (e.g., an electrical generator), but it will be appreciated that the concepts discussed herein are equally applicable to other equipment as well. Additional examples of devices having a rotating shaft include gearboxes, such as a windmill gearbox, pumps, compressors, drive shafts, axles, and the like. Maritime propulsion systems also utilize a rotating shaft.
The rotating shaft 4, a portion of which is illustrated in
A mounting fixture 10 may be used to position the shaft grounding apparatus 20 in close proximity to the rotating shaft 4. In some instances, the mounting fixture 10 may include a first end 12 mounted to a base 8, or other stationary structure, and a second end 14 mounted to the shaft grounding apparatus 20. One such mounting fixture 10, is further described in and relates to the subject matter contained in the U.S. patent application Ser. No. 13/204,176 entitled MOUNTING FIXTURE INCLUDING AN ARTICULATION JOINT filed on Aug. 5, 2011 and published as U.S. Patent App. No. 2013/0034380, which is expressly incorporated herein by reference in its entirety. However, it is understood that the mounting fixture 10 may be of any desired configuration to position the shaft grounding apparatus 20 in close proximity to the rotating shaft 4.
The shaft grounding apparatus 20 may include an electrical box 22 housing components of the shaft grounding apparatus 20. For example, the electrical box 22 may include one or more, or a plurality of brush holders 30 including brushes 32 in electrical contact with the electrically conductive peripheral surface 6 of the rotating shaft 4. The brush holders 30 may also include a handle 34 for removing the brush holder 30 from the electrical box 22. In some instances, the brush holders 30 may be similar to those described in U.S. Pat. No. 7,034,430. The electrical box 22 may also include a control box 24 for controlling the flow of electricity from the electrical box 22.
The shaft grounding apparatus 20 may also include a rope guide 50 extending from the electrical box 22. For example, the electrical box 22 may include first and second side panels 26 secured (e.g., bolted) to a mount 28 of the mounting fixture 10 and to the rope guide 50.
Turning to
Depending on the diameter of the rotating shaft 4, and thus the length of the grounding rope 40, the rope guide 50 may include one, two, three, four, five, six or more articulating segments 52 pivotably coupled together at hinge points 62. For example, the illustrated rope guide 50 includes a first articulating segment 52a, a second articulating segment 52b, a third articulating segment 52c, a fourth articulating segment 52d, and a fifth articulating segment 52e, with a first hinge point 62a between the first and second articulating segments 52a, 52b, a second hinge point 62b between the second and third articulating segments 52b, 52c, a third hinge point 62c between the third and fourth articulating segments 52c, 52d, and a fourth hinge point 62d between the fourth and fifth articulating segments 52d, 52e. The first articulating segment 52a may also be pivotably coupled to the connector segment 56 at a hinge point 66. One such adjustable grounding rope guide is further described in and relates to the subject matter contained in the U.S. Pat. No. 8,493,707 entitled GROUNDING ROPE GUIDE FOR A DYNAMO-ELECTRIC MACHINE filed on Aug. 5, 2011, which is expressly incorporated by reference herein in its entirety.
The electrical pathway for grounding the rotating shaft 4 may be further understood with reference to
The grounding rope 40 may include a first end 42 coupled to a component in the electrical box 22 and a second end 44 hanging over the rotating shaft 4 in the direction of rotation of the rotating shaft 4. In some instances, the grounding rope 40 may have a length such that about 1 to 2 inches of the grounding rope 40 extends along the tangent line beyond the tangent between the conductive surface 6 and the grounding rope 40.
In some embodiments, the first end 42 of the grounding rope 40 may be secured to a rope holder 30 in the electrical box 22. For example, the first end 42 of the grounding rope 40 may be clamped between two plates of the rope holder 30 in some instances. From the terminal of the rope holder 30, the electrical pathway may pass through the control box 24 to a grounding wire 36 to ground 38. Thus, the grounding rope 40 may be connected to ground 38 through the electrical pathway passing through the electrical box 22, and thus grounded. In other embodiments, the first end 42 of the grounding rope 40 may be attached directly to ground 38 (e.g., a grounding post), or another component electrically coupled to ground 38, without being attached to the rope holder 30.
The shaft grounding apparatus 20 may be mounted proximate to the rotating shaft 4 to electrically ground the shaft 4 of the electric machine 2. For example, the grounding rope 40 may be placed in contact with the circumferential surface 6 of the rotating shaft 4. For instance, the grounding rope 40 may be draped over the rotating shaft 4 with the free second end 44 of the grounding rope 40 extending in the direction of rotation of the rotating shaft 4. It is noted that in some instances, multiple grounding ropes 40 (depending on the number of channels 70 provided in the rope guide 50) may be draped over the rotating shaft 4 to position the ropes 40 in contact with the surface 6 of the rotating shaft 4.
The adjustable rope guide 50 may also be positioned around a portion of the circumferential surface 6 of the rotating shaft 4 with the rope 40 extending along the channel 70 of the rope guide 50. In instances in which the rope guide 50 includes multiple channels 70, a rope 40 may be positioned in and extend along each channel 70 of the rope guide 50.
In order to accommodate the radius of curvature of the rotating shaft 4 such that the radius of curvature of the articulating segments 52 of the rope guide 50 closely matches the radius of curvature of the rotating shaft 4 and the lower edges of the articulating segments are positioned proximate the surface 6 of the rotating shaft 4, adjacent articulating segments 52 of the rope guide 50 may be pivoted relative to each other to adjust the radius of curvature of the adjustable rope guide 50. Thus, the rope(s) 40 may be circumferentially and/or axially constrained in the channel(s) 70 of the rope guide 50 along a portion of the circumference of the rotating shaft 4.
In some instances, the connector segment 56 and the articulating segments 52 of the rope guide 50 may be adjusted from a first minimum extent having a radius of curvature of 10 inches or less, 8 inches or less, or 6 inches or less to accommodate a similarly sized rotating shaft 4 to a second maximum extent having a radius of curvature of 10 inches or more, 12 inches or more, 14 inches or more, 16 inches or more, 18 inches or more, or 20 inches or more to accommodate a similarly sized rotating shaft 4. In some instances, the articulating segments 52 may be adjusted to extend substantially flat, thus accommodating rotating shafts 4 having an infinitely large diameter. Accordingly, through the adjustability of the rope guide 50, the rope guide 50 may be mounted to a range of sizes of rotating shafts 4, such as shafts 4 having diameters in the range of 6 to 36 inches, in the range of 6 to 24 inches, in the range of 6 to 20 inches, in the range of 6 to 18 inches, in the range of 6 to 16 inches, in the range of 6 to 14 inches, or in the range of 6 to 12 inches, in some instances.
Once the rope guide 50 has been adjusted to the desired radius of curvature to accommodate the diameter of the rotating shaft 4, the hinge points 62, 66 may be clamped to prevent further pivotable movement between adjacent guide segments 52, and between the connector segment 56 and the first guide segment 52a. Additional features of the rope guide 50, as well as the grounding rope 40, may be found in U.S. Patent Publication No. 2015/0070810 entitled GROUNDING ROPE FOR A SHAFT GROUNDING APPARATUS OF A DYNAMO-ELECTRIC MACHINE, filed on Sep. 9, 2014 and incorporated herein by reference in its entirety.
Accordingly, the rope guide 50 may guide the grounding rope(s) 40 along the rotating surface 6 of the rotating shaft 4. The grounding rope(s) 40 may be electrically grounded (e.g., connected to ground) to draw stray electrical voltage off of the rotating shaft 4 to prevent electrical current flow through bearings and/or other components of the electric machine 2 which could adversely affect the electric machine 2.
A processor 82 is operably coupled with the electrical sensor 85 and is configured to receive and analyze data from the electrical sensor 85. A memory 88 is operably coupled with the processor 82 and is configured to store information processed by the processor 82 that is representative of data provided by the electrical sensor 85. In some cases, the memory 88 may represent short-term memory being used by the processor 82 for buffering incoming data from the electrical sensor 85. In some instances, the memory 88 may also be used for longer term storage of information that is representative of data provided by the electrical sensor 85.
In some instances, the electrical sensor 85 is configured to periodically provide the detected electrical parameter to the processor at a sampling rate that is related to a rotation speed of the rotating shaft. In some cases, the processor 82 may be configured to periodically sample a value of an electrical parameter provided by the electrical sensor 85. In some cases, the time period between successive samplings of a value of an electrical parameter provided by the electrical sensor 85 may be selected such that an angular shaft position of the rotating shaft 4 corresponding to a particular sampling point is offset from an angular shaft position of the rotating shaft 4 corresponding to a subsequent sampling point. In other words, each successive sampling of the electrical parameter may be taken at a position or sampling point around the rotating shaft 4 which is angularly offset from the previous sampling position or sampling point. The sampling points may, for example, be timed such that the processor 82 receives or processes one or more distinct sampling points per rotation of the rotating shaft 4. In some cases the sampling points may be timed such that the processor 82 receives or processes one distinct sampling point per one, two or more rotations of the rotating shaft 4. In some instances, a series of sampling points may be timed such that each sampling point corresponds to a different point on a subsequent waveform, whether a subsequent waveform corresponds to the next rotation of the rotating shaft 4, or the subsequent waveform corresponds to a later rotation of the rotating shaft 4.
As an example, in some cases, the sampling rate at which the electrical parameter from the electrical sensor 85 is sampled may be related to the rotation speed of the rotating shaft 4 such that a particular sampling corresponds to an angular position of the rotating shaft 4 that is rotationally advanced (e.g., angularly offset) of the angular position of the rotating shaft 4 corresponding to an immediately previous sampling. In some cases, the sampling rate at which the electrical parameter from the electrical sensor 85 is sampled may be related to the rotation speed of the rotating shaft 4 such that a particular sampling corresponds to an angular position of the rotating shaft 4 that is rotationally retarded (e.g., angularly offset) of the angular position of the rotating shaft 4 corresponding to an immediately previous sampling.
In some cases, when sampling the electrical parameter provided by the electrical sensor 85, the processor 82 may be configured to sample the value of the electrical parameter from the electrical sensor 85 and record the value to the memory 88 in response to a periodic trigger. The periodic trigger may, for example, be based upon a rotational speed of the rotating shaft 4. In some cases, the periodic trigger may be based upon a rotational (angular) position of the rotating shaft 4. In some cases, the periodic trigger may include an incremental delay so that each successive sampling of an instantaneous value of the electrical parameter from the electrical sensor 85 corresponds to a different portion of a successive waveform. In some cases, the value of the electrical parameter from the electrical sensor 85 may be an amplitude of a waveform representing the electrical parameter from the electrical sensor 85.
In some cases, the processor 82 may be further configured to correlate the reconstructed waveform to relative positions of the rotating shaft in order to determine where on the rotating shaft any anomalous or threshold conditions may be occurring. If any anomalous or threshold conditions are occurring, it can be beneficial to know where on the rotating shaft 4 a possible problem is developing. In some cases, for example, the processor 82 may be further configured to utilize an indication of shaft rotational speed, in combination with knowing how frequently a sample is being taken, in order to correlate the reconstructed waveform to relative positions of the rotating shaft 4. As another example, in some cases the processor 82 is further configured to, when periodically sampling a value of the electrical parameter from the electrical sensor 85 and recording the value to the memory 88, to also record to the memory 88 a corresponding shaft rotational position that is temporally aligned with the value of the electrical parameter from the electrical sensor 85. The processor 82 may then use the temporally aligned recorded shaft rotational positions to correlate the reconstructed waveform to relative positions of the rotating shaft 4.
As used herein, continuous sampling is sampling that occurs at a repeated interval and provides a sequential sequence of samples. For example, as opposed to an analog signal, which is truly continuous, a digital signal may be considered as meeting the definition provided herein of continuous sampling as referring to sampling that occurs at a repeated interval as a function of the sampling frequency. Thus, continuous sampling may refer to repeated sampling at a known interval.
It will be appreciated that the INPUT FROM CURRENT SENSOR 84 and/or the INPUT FROM VOLTAGE SENSOR 86 may each independently represent a data channel providing data to the processor 82. The memory 88 may be operably coupled with the processor 82 and may, for example, be used to store, e.g., buffer, data provided directly from the INPUT FROM CURRENT SENSOR 84 and/or the INPUT FROM VOLTAGE SENSOR 86. In some cases, the memory 88 may also store data that has been processed by the processor 82 and thus may, for example, be representative of data that was provided from the INPUT FROM CURRENT SENSOR 84 and/or the INPUT FROM VOLTAGE SENSOR 86. A communications module 90 may be operably coupled to the processor 82 in order to communicate data to a location remote from the electric machine 2, such as a control room 92. In some cases, the communications module 90 may be used for receiving instructions and other data from the control room 92. It will be appreciated that the control room 92 may, for example, refer to an on-site control room that is proximate the location of the electric machine 2. In some cases, the control room 92 may refer instead to a remote facility, a cloud-based data collection system, a cloud-based monitoring system, and the like.
In other instances, the monitoring system 94 may include only one of the current sensor 96 and the voltage sensor 98, and be configured to calculate an electrical voltage based on a sensed electrical current from the current sensor 96 or calculate an electrical current based on a sensed electrical voltage from the voltage sensor 98. For example, an electrical shunt having a 1 Ohm resistor may be used such that electrical current equals electrical voltage, although others can be used as well, such as a shunt having a 10 Ohm resistor, a 100 Ohm resistor, a 1000 Ohm resistor, and the like.
The monitoring system 102 may, for example, include a processing module 104 that houses the processor 82, the memory 88 and the communications module 90 as discussed with respect to
In some instances, a potential anomalous or threshold condition may be a current spike that lasts longer than a particular length of time, or perhaps a current spike that reaches a current level that exceeds a threshold current value. These thresholds may be programmed into the processor 82, or may be manually entered into the monitoring system 102. In some cases, a potential anomalous or threshold condition may not be related to a current spike, but may instead pertain to an instruction received from the control room 92 (
In some cases, the processor 82 may calculate one or more values that are representative of the sampled data points, and may save the one or more representative values to the memory 88. Any variety of representative values may be calculated and saved. For example, the processor 82 may calculate an average current value and/or a peak current value. In some cases, the processor 82 may also conduct waveform analysis of the reconstructed waveform in order to look for particular patterns that indicate particular issues. For example, a saw tooth waveform with a slow rise and subsequent rapid discharge can indicate the build-up and release of static electricity on the rotating shaft 4.
In operation, a sampling point 112, labeled as “1”, is made in response to the trigger signal 104. When the next trigger signal 104 occurs, the sequential delay 110 is added before the next sampling point 114, labeled as “2” is made. This continues with a sampling point 116, labeled as “3” is made, then a sampling point 118, labeled as “a−1”, followed by a sampling point 120, labeled as “a”. The sensed parameter (electrical current or voltage) may be sampled at each sampling point 112, 114, 116, 118, 120 through less than one revolution of the rotating shaft 4, such as through 10 degrees of rotation or less, 5 degrees of rotation or less, 4 degrees of rotation or less, 3 degrees of rotation or less, 2 degrees of rotation or less, or 1 degree of rotation or less of the rotating shaft 4. It will be appreciated by looking at the relative locations of the sampling points 112, 114, 116, 118 and 120, that each sampling point is at a different location on the waveform represented by the input signal 102, corresponding to a different rotational position around the rotating shaft 4. This can also be seen in the reconstructed waveform 108, in the relative spacing of the sample points “1”, “2”, “3”, . . . “a−1” and “a”. Thus, the reconstructed waveform 108 may be a compilation of sequential sample points at different rotational positions of the rotating shaft 4 taken during multiple revolutions of the rotating shaft 4, that when compiled together form the reconstructed waveform 108 representative of the sensed parameter (electrical current or voltage) throughout a single revolution of the rotating shaft 4. As can be seen, the reconstructed waveform 108 provides a reasonable approximation to the original input signal 102. Due to the repetitive nature of the input signal from the rotating shaft 4, the reconstructed waveform 108 may be representative of the sensed parameter (electrical current or voltage) throughout a single revolution of the rotating shaft 4. A finer approximation may be obtained, for example, by reducing the sequential delay 110. It is feasible, therefore, to obtain a reasonable approximation of the original waveform while reducing data sampling requirements.
In some cases, as illustrated, it can be seen that the periodic trigger signal 104 is timed such that a sampling point occurs once every other shaft revolution. In some cases, the periodic trigger signal 104 may instead be timed such that a sampling point occurs once each shaft revolution. If desired, the periodic trigger signal 104 may be timed to permit multiple sampling points per each shaft revolution. In other instances, the periodic trigger signal 104 may be timed such that a sampling point occurs every third, fourth, fifth, or sixth revolution, or less frequently, if desired. In some cases, the timing of the periodic trigger signal 104 may be a function of how rapidly the shaft is rotating (i.e., a function of the rotational speed of the shaft), or perhaps how predictable or unpredictable the waveform that is being sampled actually is. In some cases, it is contemplated that the timing of the periodic trigger signal 104 may be adjusted in real time or in near-real time to accommodate changes in performance. For example, if the waveform appears to be changing, the timing of the periodic trigger signal 104 may be adjusted to permit more frequent sampling.
Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present invention as described in the appended claims.
Cutsforth, Robert S., Cutsforth, Dustin L., Jahnke, David A.
Patent | Priority | Assignee | Title |
Patent | Priority | Assignee | Title |
3831160, | |||
4163227, | May 01 1978 | General Electric Company | Apparatus for monitoring arcing of brushes in a dynamoelectric machine |
4406991, | Feb 04 1982 | ASEA BROWN BOVERI, INC | High power resonance filters |
4426641, | Mar 31 1980 | Hitachi, Ltd. | Method and apparatus for monitoring the shaft vibration of a rotary machine |
4451786, | Mar 01 1982 | General Electric Company | High sensitivity brush arcing monitor for a dynamoelectric machine |
4831295, | Nov 19 1986 | Alstom | Arrangement for reducing shaft voltages in dynamoelectric machines |
4873512, | Mar 20 1984 | SIEMENS POWER GENERATION, INC | Active shaft grounding and diagnotic system |
4987009, | Oct 09 1987 | TDK Corporation | Producing method of thick film complex component |
5006769, | Apr 05 1989 | Alstom | Arrangement for detecting winding shorts in the rotor winding of electrical machines |
5198713, | Apr 19 1989 | Olympus Optical Co., Ltd. | Ultrasonic transducer apparatus |
5233499, | Aug 21 1991 | SIEMENS ENERGY, INC | Automatic shaft ground conditioner |
5297721, | Nov 19 1992 | FRY S METALS, INC | No-clean soldering flux and method using the same |
5461329, | Jan 21 1992 | Martin Marietta Energy Systems, Inc. | Method and apparatus for generating motor current spectra to enhance motor system fault detection |
5488281, | Sep 28 1994 | Allen-Bradley Company, Inc. | Method and apparatus for predicting winding failure using zero crossing times |
6460013, | May 06 1999 | BRITTINGHAM, PAMELA J | Shaft voltage current monitoring system for early warning and problem detection |
6714020, | Jul 27 2001 | GENERAL ELECTRIC TECHNOLOGY GMBH | Protective and monitoring apparatus for a generator, and use of such a protective and monitoring apparatus |
7034430, | Dec 18 2001 | CUTSFORTH, INC | Brush holder apparatus, brush assembly, and method |
7034706, | May 06 1999 | BRITTINGHAM, PAMELA J | Early warning and problem detection in rotating machinery by monitoring shaft voltage and/or grounding current |
7102379, | Sep 10 2002 | GENERAL ELECTRIC TECHNOLOGY GMBH | Apparatus and method for monitoring and/or analysis of electrical machines during operation |
7117744, | Sep 10 2002 | GENERAL ELECTRIC TECHNOLOGY GMBH | Apparatus and method for detecting vibrations of the shaft assembly in an electrical machine |
7212010, | Aug 12 2004 | GENERAL ELECTRIC TECHNOLOGY GMBH | Method and device for detecting a contact point on a shaft of a rotating machine |
7649470, | Sep 10 2002 | GENERAL ELECTRIC TECHNOLOGY GMBH | Method and apparatus for detection of brush sparking and spark erosion on electrical machines |
7705623, | Jul 13 2006 | GENERAL ELECTRIC TECHNOLOGY GMBH | Method and device for detecting interlaminar short circuits |
7830031, | Mar 19 2007 | Vestas Wind Systems A/S | Protection system for an electric generator, wind turbine and use hereof |
8396677, | Dec 07 2007 | GENERAL ELECTRIC TECHNOLOGY GMBH | Method for monitoring the shaft current and/or the insulation of the shaft of electric machines and device for performing the method |
8493707, | Aug 05 2011 | CUTSFORTH, INC.; Cutsforth Products, INC | Grounding rope guide for a dynamo-electric machine |
8714860, | Aug 05 2011 | CUTSFORTH, INC.; Cutsforth Products, INC | Mounting fixture including an articulation joint |
9046579, | Feb 24 2010 | Siemens Aktiengesellschaft | Electric arc discharge evaluation method, and associated test stand |
9088197, | Sep 07 2011 | WOLONG ELECTRIC AMERICA LLC | Shaft grounding system |
9209667, | Aug 05 2011 | CUTSFORTH, INC. | Grounding rope guide for a dynamo-electric machine |
9560729, | Sep 09 2013 | CUTSFORTH, INC. | Grounding rope for a shaft grounding apparatus of a dynamo-electric machine |
20020101396, | |||
20050183504, | |||
20050184751, | |||
20050200378, | |||
20060043977, | |||
20080163893, | |||
20090008945, | |||
20090179663, | |||
20100299090, | |||
20110301873, | |||
20130032373, | |||
20130034380, | |||
20150070810, | |||
20160266206, | |||
20170285086, | |||
20180026498, | |||
CA2498105, | |||
WO2017060218, |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Jun 04 2018 | CUTSFORTH, INC. | (assignment on the face of the patent) | / | |||
Jun 21 2018 | JAHNKE, DAVID A | CUTSFORTH, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 046299 | /0469 | |
Jun 21 2018 | CUTSFORTH, ROBERT S | CUTSFORTH, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 046299 | /0469 | |
Jun 21 2018 | CUTSFORTH, DUSTIN L | CUTSFORTH, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 046299 | /0469 |
Date | Maintenance Fee Events |
Jun 04 2018 | BIG: Entity status set to Undiscounted (note the period is included in the code). |
Jun 25 2018 | SMAL: Entity status set to Small. |
Jul 01 2024 | REM: Maintenance Fee Reminder Mailed. |
Date | Maintenance Schedule |
Nov 10 2023 | 4 years fee payment window open |
May 10 2024 | 6 months grace period start (w surcharge) |
Nov 10 2024 | patent expiry (for year 4) |
Nov 10 2026 | 2 years to revive unintentionally abandoned end. (for year 4) |
Nov 10 2027 | 8 years fee payment window open |
May 10 2028 | 6 months grace period start (w surcharge) |
Nov 10 2028 | patent expiry (for year 8) |
Nov 10 2030 | 2 years to revive unintentionally abandoned end. (for year 8) |
Nov 10 2031 | 12 years fee payment window open |
May 10 2032 | 6 months grace period start (w surcharge) |
Nov 10 2032 | patent expiry (for year 12) |
Nov 10 2034 | 2 years to revive unintentionally abandoned end. (for year 12) |